Field of the Invention
The invention relates to the field of manufactured radio frequency devices. More particularly, the present invention relates to a radio frequency shield for use in association with a coaxial cable connector.
Discussion of the Related Art
In cable television and satellite television systems (“CATV”) reduction of interfering radio frequency (“RF”) signals improves signal to noise ratio and helps to avoid saturated reverse amplifiers and related optic transmission that is a source of distortion.
Past efforts have limited the ingress of interfering RF signals into CATV systems. These efforts have included increased use of traditional connector shielding, multi-braid coaxial cables, connection tightening guidelines, increased use of traditional splitter case shielding, and high pass filters to limit low frequency spectrum interfering signal ingress in active home CATV systems.
While it appears the industry accepts the status quo as satisfactory, there remain, in the inventor's view, good reasons to develop improvements further limiting the ingress of interfering RF signals into CATV systems.
One significant location of unwanted RF signal and noise ingress is in the home. This occurs where the subscriber leaves a CATV connection such as a wall-mounted connector or coaxial cable drop connector disconnected/open. An open connector end exposes a normally metallically enclosed and shielded signal conductor and can be a major source of unwanted RF ingress.
The F connector is the standard connection used for cable television and satellite signals in the home. For example, in the home one will typically find a wall mounted female F connector or a coaxial cable “drop” including a male F connector for supplying a signal to the TV set, cable set-top box, or internet modem. Notably, wall mounted female F connectors are connected via a coaxial cable terminated with male connectors at opposite ends.
Whether a CATV signal is supplied to a room via a drop cable or via a wall mounted connector, each one is a potential source of unwanted RF signal ingress. Wall mounted connectors can be left open or a coaxial cable attached to the wall mounted connector can be left open at one end. Similarly, drop cables terminated with a male F connector can be left open.
Multiple CATV connections in a home increase the likelihood that some connections will be left unused and open, making them a source of unwanted RF ingress. And, when subscribers move out of a home, CATV connections are typically left open, another situation that invites RF ingress in a CATV distribution system.
A method of eliminating unwanted RF ingress in a CATV system is to place a metal cap over each unused F connector in the home or, to place a single metallic cap over the feeder F port at the home network box. But, the usual case is that all home CATV connections are left active and open, a practice the industry accepts to avoid expensive service calls associated with new tenants and/or providing the CATV signal in additional rooms.
The inventor's experience shows current solutions for reducing unwanted RF ingress resulting from open connectors are not successful and/or not widely used. Therefore, to the extent the CATV industry recognizes a need to further limit interfering RF ingress into CATV systems, it is desirable to have connectors that reduce RF ingress when they are left open.